SAMAC Articles

Accident Reconstruction: Event Data Recorders (EDR)

Everyone in the auto insurance industry is aware that recorded data may be available from vehicles after a collision. This data is stored in event data recorders, often incorrectly referred to as “black boxes”. Currently data can be found in one of 3 types of systems, depending on the type of vehicle and fleet owner. These are:

  1. Passenger vehicles: Data in passenger vehicles is normally stored in the airbag module (ACM/RCM/EDR) as the result of a collision or airbag deployment, and can include vehicle speeds, speed changes, brake status (on/off), throttle position, and driver seatbelt use, among others. As well, some Fords have had additional data stored in the powertrain control module (PCM). Generically, the modules are known as Event Data Recorders (EDR’s) if event data is stored on them. Currently, vehicles for which data may be available include Chrysler, General Motors, Ford, and Toyota. More manufacturers will become available in 2012 & 2013. Specific models with data that may be available are listed on the following site: This site is also useful to review for more background information. Weeklong training is required every two years along with specialized equipment in order to download and interpret the data. SAMAC currently has 4 experts with the training and equipment to download these vehicles. Although the retrieved data can be very useful, there are many times when the data is not available, retrievable, or useful.
  2. Heavy trucks: The data available from heavy truck incidents varies widely but can include hard stop and collision data. If available, the data will be stored on the engine control modules of the truck or sometimes in add-on equipment installed by the fleet owner in the cab. SAMAC experts have routine experience in downloading this information via the engine manufacturers as the equipment, software updates and training are very expensive.
  3. Diagnostic codes, etc: These codes register the status of various systems in a modern vehicle and are routinely downloaded by vehicle dealers and repair shops during service checks. These downloads can also be obtained by using a commercially available tool (such as Snap-On) with the appropriate software. The data is of limited use in accident reconstruction except for manufacturers that might want to verify that there were no fault codes for their airbag or other safety systems. Although typically performed by dealers, SAMAC has the capability and training to perform such downloads.